THE IMPENETRABLE SEA 



fessed to find, and actually drew and described, the 

 digestive, circulatory and respiratory organs of the ''para- 

 site" — parasite to him no longer. 



Kolliker's error is perpuated for all time in the Hecto- 

 cotylus octopodis, which is not an animal at all, for as was 

 subsequently shown it does not breathe or eat and has no 

 heart. 



Heinrich Miiller (1820-60), the celebrated German 

 anatomist, solved the dual problem in 1853. While 

 working in Messina he examined a number of very small 

 argonauts which had no shells and were a different shape 

 from any he had hitherto seen. He found among the 

 arms of each specimen a sac that when opened contained 

 a coiled Hectocotylus . This was at last seen to be the 

 modified sexual arm of the male, which breaks oflf and 

 stays in the female. 



The female's body measures up to six inches across, 

 with arms stretching out from it varying in length up 

 to eighteen inches long, so that the creature has a span 

 of anything from two to three feet. This means that the 

 beautiful shell which contains the body would also be 

 anything up to twelve inches across. But the male is a 

 tiny creature compared with its mate. It has a little 

 thimble-shaped body with a mantle less than a quarter 

 of an inch long, while its arms are about half an inch in 

 length. The body of the female often has a diameter 

 twenty times that of the male — a difiference in size which 

 might be illustrated by comparing a coco-nut with a 

 small marble. In the male argonaut the sperm duct is in 

 its third left arm, in a tiny sac. This eventually bursts and 

 from within it the Hectocotylus unwinds until it attains a 

 length of five inches — ten times the length of the male 

 argonaut himself. Very little is known of the details of 

 mating, but the elongated third arm certainly fertilizes 

 the female, either while attached to the tiny male or after 

 it has broken away. We do know that the female often 

 carries the male around with her, tucked away in her shell. 



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